now you're a real fisherman. [ male announcer ] humana. >>> our third story "outfront," iran refuses to budge despite some talk about possibly suspended some parts of its nuclear program. officials tell cnn tonight, the iranians don't appear to be conceding any real ground. sent the iranian currency plunging, as much 40%. that has sparked angry protests. the u.s. is stepping up pressure with a show of military force in the persian gulf. this is a tense and exciting situation in many ways because of the possibilities out there. chris lawrence is "outfront." >> imminent surface threat. >> reporter: if fighting breaks out with iran in the persian gulf, it will look a lot like this drill. us navy sailors making split second decisions on whether to fight. >> i ask, would you shoot? knowing you're responsible for the lives of everybody on board? that's a tough one. if you get it right, congratulations. >> reporter: but the biggest battles could be fought under water. >> no one goes out unless someone has put mines in the water. >> reporter: a $1